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module Internal.XPlus where
import Internal.Marking
import XMonad
-- The X Monad with additional information. Used for configuring the system.
data XPlusState l =
XPlusState {
markContext :: MarkContext
, xConfig :: XConfig l
}
data XPlus l a = XPlus (XPlusState l -> X (a, XPlusState l))
instance Functor (XPlus l) where
fmap fn (XPlus xfn) =
XPlus $ \st -> do
(a, b) <- xfn st
return (fn a, b)
instance Applicative (XPlus l) where
pure = return
(<*>) afn aarg = do
fn <- afn
arg <- aarg
return (fn arg)
instance Monad (XPlus l) where
-- (>>=) :: XPlus l a -> (a -> XPlus l b) -> XPlus l b
(>>=) (XPlus afn) bfn = do
XPlus $ \s0 -> do
(a, s1) <- afn s0
let (XPlus xBFn) = bfn a
xBFn s1
return x = XPlus $ \s -> return (x, s)
getXPlusState :: XPlus l (XPlusState l)
getXPlusState = XPlus $ \s -> return (s, s)
getXConfig :: XPlus l (XConfig l)
getXConfig = xConfig <$> getXPlusState
getMarkContext :: XPlus l MarkContext
getMarkContext = markContext <$> getXPlusState
runXPlus :: MarkContext -> XConfig l -> XPlus l a -> X a
runXPlus markCtx cfg (XPlus fn) = do
fst <$> fn (XPlusState markCtx cfg)
liftXPlus :: X a -> XPlus l a
liftXPlus xa = XPlus $ \s -> (\a -> (a, s)) <$> xa
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